Lifting jack



A. H.. F. HERN.

LIFTING JACK.

APPLICATION FILED ocr. 19. 1920.

Patented Sept. 26, 1922;

2 SHEETSSHEET l- A. H. F. HERN.

LIF'IING JACK.

APPLICATION FILED ocr.19.'1920.

1 $29,945,- PatentedSept. 26, 1922.

2 SHEETS-SHEET 2.

. INVENTOR BY Aiiil'i'Helm/ mun-MY Patented Sept. 26, 1922.

can s'm'rss PATENT OFFICE.

ALBERT HENRY FEE HERN', OF LONDON, ENGLAND.

- LIFTING TACK.

Application filed October 19, 1920. Serial No. 18,@85

for use with automobiles, aeroplanes, 'airships and other vehicles. The device is also suitable for other uses, where it is desired to provide an expansible or contractable means for exerting pressureor sustaining a load.

According to this invention, there is provided in combination with a lifting-jack or the like of any desired type, a container therefor, wherein the jack can be collapsed and entirely contained. The container or box is preferably provided with a lid so that it can be closed when the jack is notin use,

and this lid may, if desired, be spring-controlled to remain in its closed position. With this construction the operation of the jack in expanding, automatically ,opens the lid of the box, and in contracting, permits the lid to be closed by its spring control.

According to another feature of this invention, the preferred type of lifting-jack is one that operates on the lazy-tongs principle. In mechanism of this type, pairs of links are pivoted together intermediate of their ends so that they can be inclined to one another, and these links are connected at their ends to pairs" of other links. \Vhen the device is closed all the links lie compactly side-by-side, and it is opened or extended by moving towards oneanother the 4p similarly situated ends of a pivoted pair of links, which ends, in the closed position of the device, are remote from one another. In order to make the lifting-jack stable when in use, it is customary to provide two such lattices arranged side-by-side, the various pivot pins being common to both lattices. According to another feature of this invention a lifting-jack of'theltype above described is operated by a screw engaging nuts -or blocks which are connected respectively to-the pivot pins whereby the end of one link engages the end of another link, so that the expansion of the lattice takes place in two opposite directions from the'said blocks.

This invention also covers the specific construction of lifting-jack hereinafter described, and illustrated.

In the accompanying drawings,

Figure 1 is a side elevation showing the jack extended from its container, one side of the container being removed;

Figure 2 is an end elevation of Figure 1;

Figure 3 shows a detail of construction; 7

Figure 4 shows the operating handle for the jack; I

Figure 5 shows an alternative formof operating handle; Figures 6- and 7 show a modified form of jack, and two different methods of attaching 1t to a vehicle or part which is to be lifted by the jack;

Like reference characters indicate like parts throughout the drawings.

Referring first to Figures v1 and 2, the

jack is mounted upon a suitably substantial base 10 which is mounted in a container or has side walls 11 resting on a plinth, secured to it, as by the screws 12, to constitute a container. The base 10 which rests on the ground may be slightly hollowed out at the. middle of the underside as shown in Figure 1, and the ends of its lower surface are curved upwardly asis also shown in Figure 1 This shaping facilitates the sliding of the jack on any surface, as for example, when ithas to be slid along the ground underneath a motor vehicle, or withdrawn therefrom.

Near each end of the upper surface of the base there are provided bosses 13, which are preferably symmetrical about the centre line of the length of the base. These bosses 13 may be connected by a web or Webs l4c'if it is desired to stiffen the base.

Pivot pins 15 and 16 are mounted in each of the bosses 13 with their ends projecting therefrom, and a lattice-work is pivotally mounted on these pins. As the construction of the lattice-work or linkage is the same at each side of the base, the description will refer to one side only, for simplicity. Upon each of the pins 15, 16, there are. pivoted links '17, 18,,these links extending towards and crossing one another. of these links are pivotally connected at 19, 20 with various other links. The pivots The upper ends.

operating spindle for the 'ack. .The pivots 19, 20, aforesaidengage-t e upper ends of the links-'23, 24, which are pivoted together on a pin 25 at their lower end, and this in rides in a slot 26 in a bracket 27 upstanding from the base 10.

The pivots 19, 20, also engage respectively the lower ends of-crossed links 28, 29, which are pivoted together at or near the middle of their length on a pivot pin 30. The upper ends of these links 28, 29, are pivoted on pins 31, 32, respectively. A pair of links 33, 34, are pivoted at their lower ends upon the pivot pins 31, 32 respectively and at their upper ends on a pin 35 common to both of them. This pin 35 engages a block or crutch 36 which is suitably shaped according to the purpose for which the device is to be used. In the case of a lifting-jack this crutch .36 is suitably shaped for engaging the underside of the axis of a vehicle. The pin 35 may extend through a hole in the crutch 36, or it may lie at the -"'upper end of a vertical slot 37, it being necessary only that any weight applied to the crutch 36 should be supported by the pivot pin 35. There is also provided a second pair of links 38, 39, Which are pivoted at their lower ends upon the pivot pins 31, 32, aforesaid. These links are connected together at their upper end to a pivot pin 40 common to the two of them, and thisipin 40 rides in the slot 37 in the crutch 36.

The function of the links 38, 39 is to prevent the crutch 36 from swinging on the pivot pin 35 so that its upper surface remains effectively parallel with the base 10. This control of the crutch 36 against swinging is effective at all heights to which the jack may be raised, sirice the pivot pin 40 is always in engagement with the slot 37 aforesaid.

As above stated, the linkage above described is duplicated, as is seen most clearly in Figure 2, and the pivot pins 35 and 40 which engage the crutch 36 are common to both sets of the linkage. The blocks 21, 22 aforesaid also engage each set of linkage.

As above stated, the blocks 21, 22 receive the operating spindle for this jack. The block 21 is screw-threaded internally to engage with a similar thread on the spindle 42, and it is preferred to use a buttress thread on the spindle as illustrated in Figure 1. The end of the spindle which engages the block 22 is turned smooth and the block is bored to receive this end, as shown in Figure 3, the end of the spindle being indicated at 43. A ball thrust race 44 is provided in the block 22 and the spindle 42 is retained against endwise movement through the block by a nut 45 screwed on the end thereof, locked .by a grub-screw or split-pin and engaging the ball-race aforesaid. The spindle is further provided with a shoulder 46 engaging the other face of the block 22. Instead of using the hereinbefore described construction of the blocks 21, 22 and spindle 42, any other desired arrangement may be provided. Thus, for-example, the spindle could be provided with right and left-handed upon it one element 50 of a universal (-oupling. The other element 51 of this coupling is suitably shaped as at 52 to engage the pin 48 on the spindle 42, and preferably the engagement is of the bayonet-joint type, for the purpose hereinafter set forth. The shaft 49 is provided with a handle 53 which may be shaped as illustrated in Figure 4, or as at 54 in Figure 5.

- The container 11 is provided with a slot 55, see Figure 2, in an end wall to permit the vertical movement of the spindle 42, and it is also provided with a hinged lid 56. Preferably a suitablesimple form of spring catch 57 is provided on the side of the box at the middle of its length to hold the lid closed when the jack is collapsed.

Assuming that the jack is thus collapsed and is to be put into use, say to lift one wheel of a motor car, the lid 56 of the box 11 is opened and the box placed in position on the ground underneath the axle or other convenient part of the car. The operating handle is engaged with the end 47 on the spindle 42, by the element 51 of its universal coupling so that the pin 48 engages the opening 52 therein. This handle is then turned to cause rotationof the spindle 42. It will .be appreciated that when the jack is collapsed or lowered the two blocks 21. 22 lie at opposite ends of the spindle 42, and the rotation is such as to cause them to approach one another. By this movement the linkage is extended into the position shown in Figure 1, the crutch 36 being raised from inside the box to the position illustrated. In so doing it engages the axle or other part of the car and lifts it. The function of the links 23, 24 aforesaid is to prevent any oscillation of the complete jack about the pivots 15, 16, or in other words to render it stable longitudinally of the box. The duplication of the linkage hereinbefore described and as illustrated in Figure 2, ensures similar stability r in a direction transverse to the length of the box, so that the whole structure is adequately stable. It will be ap reciated that the load is transmitted from t e crutch 36' to the pivot pin 35 and thence through the links 33 and 34, pins 31 and 32, links 28 and 29 and pivots 30, pivots 19 and 20, links 17 and 18, pins 15 and 16, to the bosses 13 on the base 10 which receive the pins 15 and 16, and all these parts can easil be made of adequate strength to sustain t e load. The links 23, 24, 38 and 39 take'no part-in sustaining a normal load, but ensure the stability of the structure.

When the jack is to be lowered, the reverse operation takes place by rotation of the spindle 42 in the opposite direction until the crutch 36 lies within. the box or container 11. The whole jack may then be withdrawn from the position in whlch it has been placed by pulling upon the operating handle since the bayonet-joint or equivalent connection of the member 51 with the pin 48 in the spindle, prevents the parts being disengaged by a direct pull.

If it is desired, the handle or operating rod may be ermanently attached to the end of the spin le 47 by a universal coupling, the other end of the rod being supported in any convenient-position and by any suitable means. This construction is particularly suitable in cases inwhich the jack is permanently attached to the vehicle and-is expanded downwards to effect the lifting thereof.

Such a construction is illustrated in Figure 6 wherein 59 represents an axle or other part of the vehicle to which the jack is attached. Any suitable clamping means, such as a saddle-piece 60, bolts 61 and a bridge-piece 62, are secured to the part 59 and also hold the base 63'of the jack in an inverted position so that the. container there of extends downwards. In this case the lid 65 of the container 64 constitutes the foot of the jack which engages the ground, so as to provide a support of adequate area, and when the jack is collapsed this lid is brought up to the container 64 to close it. The slot 66 in the end of the container 6.4 through which the operating spindle extends, is conveniently closed for the greater. part of its length by an upstanding plate 67 secured on or formed with the part 65 aforesaid.

In cases where it is desired that the jack should be used in aninverted position as above described, but at the same time should be detachable, a construction similar to that shown in Figure 7 may be used. The parts illustrated therein are similar to and are indicated by the same reference characters as in Figure 6, with the exception that the jack itself is not secured by the bolts 61, but the bridge-piece 62 is provided with any suitable form of slides 68 into which the base of the jack 63 may be slid when it is desired to use it. I

While the mechanism forming the. subject of this invention has been described as a lifting-jack, it will be appreciated that it may be applied to any other use where it 'is desired to exert pressure through an'extensible member.

It will be seen that the provision of a box or container for the mechanism offers several advantages. Thus the mechanism is effectively protected from damage and from wet and dust; it can be effectively lubricated, and the lubricant is not lost since the mechanism normally lies within the container; further, although the mechanism is lubricated, it can be used without soiling the hands, as the only part of the apparatus which is handled is the outside of the box, which is easily kept clean, and the mechanism does not have to be. removed from the box when it is operated. It can be easilv stowed away when carried in a motor car, for instance, without any special provision for protecting adjacent articles against contact.

The special construction of lifting mechanism hereinbefore described, also offers advantages in that the friction is reduced to a minimum, the leverage varies as the jack is extended, so that the most advantageous ratio of power to load is'obtained when the jack is approaching its fully extended position, that is to say, at the time when the load-is being lifted, and the structure is absolutely rigid at every elevation. Finally, the whole mechanism is substantial, there being .a complete absence of small parts, such as pawls, springs and the like, which are liable to break and get out of order.

Claims 1. A lifting jack comprising a base provided on its ends with hearing bosses, crossing links pivotally connected to said bosses and engaging the opposite ends of the same, a plurality of slotted members extending upwardly from the base between said bosses, bearing blocks pivotally connected to the upper ends of said links, short links having their upper ends pivotally connectedto said bearing blocks, and having their lower ends pivotally connected and slidably engaging the slot of said slotted members, one of said blocks being threaded, a screw swiveled in the other block and having its threads engaging the threads of the threaded block, second pairs of crossed links having their lower ends pivotally connected to said blocks, second pairs of short links having their lower ends pivotally connected to the upper ends of the second pairs of crossed links, a saddle pivotally connected to the upper ends of the last mentioned short links and provided with 'a vertically extending slot, a pivot pin extending through the last mentioned slot, and links having theirupper ends connected to the last mentioned pivot pin and their lower ends pivotally connected to the upper ends of the second pairs of crossed links.

2. A lifting jack of the kind defined by claim 1 in which the base is provided with upwardly extending side and end walls, the base and walls forming va container, a cover for said container and a slot provided in one of the end Walls to permit vertical movement of said screw.

3. A lifting jack of the kind defined by claim 1 in which the. screw is provided with oppositely extending lugs, and a handle member provided with a universal joint and of said box being provided with a slot in p which said spindle travels, and an operating handle for the rotatable spindle.

In testimony whereof I have signed my name to this specification.

ALBERT HENRY FEE HERN. 

